title: Thrombophilic genotypes in subjects with idiopathic antiphospholipid antibodies--prevalence and significance.
abstract: To evaluate the significance of common thrombophilic genotypes in subjects with idiopathic antiphospholipid antibodies (aPL) we determined the methylenetetrahydrofolate reductase C677-->T (MTHFR) and factor V A506-->G (FV Leiden) polymorphisms in 49 subjects with idiopathic aPL (57% of whom suffered spontaneous vein thrombosis), in 70 subjects with a history of spontaneous vein thrombosis and in 193 healthy subjects. The prevalence of MTHFR C677-->T+/+ (homozygotes) was 25%, 18% and 17% respectively amongst aPL thrombotics, non aPL thrombotics and controls and that of MTHFR C677-->T+/- (heterozygotes) was 53%, 59% and 53% respectively in the same groups. The prevalence of FV Leiden was higher in aPL thrombotics (14%) and in non aPL thrombotics (18%) than in controls (4%) (p < or = 0.05). APL thrombotics with MTHFR C677-->T+/+ had a lower mean age at first thrombotic event (22 +/- 6 years) than aPL thrombotics with MTHFR C677-->T+/- and non mutated considered together (38 +/- 14 years, p = 0.0004) and than non aPL thrombotics with MTHFR C677-->T+/+ (38 +/- 14 years, p = 0.003). FV Leiden may contribute to the hypercoagulability of a small, albeit significant proportion of thrombotic aPL subjects, whereas the association between MTHFR C677-->T+/+ and aPL may have an impact on age at first occlusive event and suggests a possible pathogenetic interaction.
authors.affiliation: Department of Haematology, St. Thomas' Hospital, London, UK. Pames@Rayne.umds.ac.uk
authors.forename: P R
authors.initials: PR
authors.lastname: Ames
authors.forename: C
authors.initials: C
authors.lastname: Tommasino
authors.forename: G
authors.initials: G
authors.lastname: D'Andrea
authors.forename: L
authors.initials: L
authors.lastname: Iannaccone
authors.forename: V
authors.initials: V
authors.lastname: Brancaccio
authors.forename: M
authors.initials: M
authors.lastname: Margaglione
mesh_terms: D000328:Adult; D017668:Age of Onset; D017152:Antibodies, Antiphospholipid / Q000097:blood*; D005165:Factor V / Q000235:genetics*; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D042965:Methylenetetrahydrofolate Reductase (NADPH2); D008875:Middle Aged; D009154:Mutation; D000587:Oxidoreductases Acting on CH-NH Group Donors / Q000235:genetics; D015995:Prevalence; D019851:Thrombophilia / Q000453:epidemiology / Q000235:genetics* / Q000276:immunology
chemical_list: D017152:Antibodies, Antiphospholipid; C095381:factor V Leiden; D005165:Factor V; D000587:Oxidoreductases Acting on CH-NH Group Donors; D042965:Methylenetetrahydrofolate Reductase (NADPH2)